Compounds useful in the synthesis of halichondrin b analogs

ABSTRACT

In general, the invention features compounds useful for the synthesis of analogs of halichondrin B, such as eribulin or pharmaceutically acceptable salts thereof, e.g., eribulin mesylate. Exemplary compounds are of formula (I), (II), or (III):

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.13/477,483, filed May 22, 2012, which is divisional of U.S. applicationSer. No. 13/014,517, filed Jan. 26, 2011, which claims benefit of U.S.Provisional Application No. 61/298,337, filed on Jan. 26, 2010, each ofwhich is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

The invention relates to compounds useful in the synthesis of analogs ofhalichondrin B.

Eribulin mesylate, a nontaxane microtubule dynamics inhibitor, is astructurally simplified, synthetic analog of the marine natural producthalichondrin B. Methods for the synthesis of eribulin and otherhalichondrin B analogs are described in International Publication No. WO2005/118565 and U.S. Pat. No. 6,214,865. New intermediates for thesynthesis of halichondrin B analogs, in particular eribulin, aredesirable.

SUMMARY OF THE INVENTION

In general, the invention features compounds useful for the synthesis ofanalogs of halichondrin B, such as eribulin, including pharmaceuticallyacceptable salts thereof, e.g., eribulin mesylate.

In one aspect, the invention provides a compound having the formula (I):

wherein X is halogen or oxo; Z is a leaving group; Q is —C(O)H,—CH═CHC(O)OY₁, —C(R)H(CH₂)_(n)OY₁, or —C(R)HCH₂C(O)OY₁; R is H or —OY₂;Y₁ and Y₂ are each independently H or a hydroxyl protecting group; and nis 1 or 2. Exemplary compounds have the formula (Ia):

In particular embodiments, Q is —(CH₂)₃OY₁, for example wherein Y₁,together with the oxygen to which it is bound, is an ester, carbonate,carbamate, sulfonate, or ether hydroxyl protecting group. For example,Y₁ is pivaloyl, acetyl, benzoyl, p-bromobenzoyl, p-methoxybenzoyl,1-naphthoyl, 2-naphthoyl, o-phthaloyl, benzyl, p-methoxybenzyl,triphenylmethyl, tri(C1-C6 alkyl)silyl, tri(C6-C10 aryl or C1-C6heteroaryl)silyl, di(C6-C10 aryl or C1-C6 heteroaryl)(C1-C6 alkyl)silyl,or (C6-C10 aryl or C1-C6 heteroaryl)di(C1-C6 alkyl)silyl.

In other embodiments, X is halogen, and/or Z is halogen or(C1-C6)alkylsulfonate (such as triflate, iodide, or bromide).

In other embodiments, the compounds are of the formula (Ib):

wherein Y₁ is H, pivaloyl, benzoyl, p-bromobenzoyl, 1-naphthoyl,2-naphthoyl, p-methoxybenzoyl, or o-phthaloyl or a salt thereof.

In certain embodiments, Q is —C(O)H, —CH═CHC(O)OY₁, or —C(R)HCH₂C(O)OY₁;X is bromo, chloro, fluoro, or oxo; or Z is halogen, C1-C12 alkoxy,C2-C12 alkylsulfonate, C2-C12 alkenylsulfonate, carbocyclic C6-C20arylsulfonate, C4-C19 heteroarylsulfonate, monocyclic C1-C6heteroarylsulfonate, (C6-C15)aryl(C1-C6)alkylsulfonate,(C4-C19)heteroaryl(C1-C6)alkylsulfonate,(C1-C6)heteroaryl(C1-C6)alkylsulfonate, or diazonium; or combinationsthereof.

In other embodiments, when Q is —(CH₂)₃OY₁, Z is triflate, and X isiodide, Y₁ is not pivaloyl; when Q is —(CH₂)₃OY₁, Y₁ is pivaloyl, and Zis triflate, X is not iodide; or when Q is —(CH₂)₃OY₁, Y₁ is pivaloyl,and X is iodide, Z is not triflate. Alternatively, when Z is triflate,and X is iodide, Q is not —(CH₂)₃OY₁.

In another aspect, the invention features compounds having the formula(II):

wherein X is halogen or oxo; Q is —C(O)H, —CH═CHC(O)OY₁,—C(R)H(CH₂)_(n)OY₁, or —C(R)HCH₂C(O)OY₁; R is H or —OY₂; n is 1 or 2;Y₁, Y₂, Y₃, and Y₄ are each independently H or a hydroxyl protectinggroup; T is oxo or —OY₅; and Y₅ is H or a hydroxyl protecting group, orY₅, together with the oxygen atom to which it is bound, is a leavinggroup. Exemplary compounds have the formula:

In particular embodiments, Q is —(CH₂)₃OY₁. In these embodiments, Y₁,together with the oxygen atom to which it is bound, can be an ester,carbonate, carbamate, sulfonate, or ether hydroxyl protecting group; Y₃and Y₄ can each, independently and together with the oxygen atom towhich it is bound, be an ester, carbonate, carbamate, sulfonate, orether hydroxyl protecting group, or Y₃ and Y₄ together with the oxygenatoms to which they are bound can be a cyclic carbonate, cyclicboronate, acetal, ketal, or cyclic silylene hydroxyl protecting group or1,1,3,3-tetraisopropylsiloxanediyl; T can be —OY₅; and/or Y₅, togetherwith the oxygen atom to which it is bound, can be an ester, carbonate,carbamate, sulfonate, or ether hydroxyl protecting group. In theseembodiments, Y₁ is, for example, pivaloyl, acetyl, benzoyl,p-bromobenzoyl, p-methoxybenzoyl, 1-naphthoyl, 2-naphthoyl, o-phthaloyl,benzyl, p-methoxybenzyl, triphenylmethyl, tri(C1-C6 alkyl)silyl,tri(C6-C10 aryl or C1-C6 heteroaryl)silyl, di(C6-C10 aryl or C1-C6heteroaryl)(C1-C6 alkyl)silyl, or (C6-C10 aryl or C1-C6heteroaryl)di(C1-C6 alkyl)silyl; Y₃ and Y₄ are, for example, eachindependently tri(C1-C6 alkyl)silyl, tri(C6-C10 aryl or C1-C6heteroaryl)silyl, di(C6-C10 aryl or C1-C6 heteroaryl)(C1-C6 alkyl)silyl,or (C6-C10 aryl or C1-C6 heteroaryl)di(C1-C6 alkyl)silyl, or Y₃ and Y₄are together di(C1-C6alkyl)silylene; and/or Y₅ is, for example, acetyl,benzoyl, p-bromobenzoyl, p-methoxybenzoyl, 1-naphthoyl, 2-naphthoyl, oro-phthaloyl.

In other embodiments, X is halogen. These compounds can also have theformula (IIc):

wherein Y₁ and Y₅ are as follows:

Y₁ Y₅ H H benzoyl benzoyl p-bromobenzoyl p-bromobenzoyl pivaloyl Hpivaloyl acetyl pivaloyl benzoyl 2-naphthoyl H 2-naphthoyl 2-naphthoyl1-naphthoyl H 1-naphthoyl 1-naphthoyl p-methoxybenzoyl Hp-methoxybenzoyl p-methoxybenzoyl o-phthaloyl or salt thereof H

A specific compound is

In another embodiment, the invention features a compound having theformula (III):

wherein Q is —C(O)H, —CH═CHC(O)OY₁, —C(R)H(CH₂)_(n)OY₁, or—C(R)HCH₂C(O)OY₁; R is H or —OY₂; n is 1 or 2; Y₁, Y₂, Y₃, and Y₄ areeach independently H or a hydroxyl protecting group; U is halogen or—OY₆; Y₅ is H or a hydroxyl protecting group or Y₅, together with theoxygen atom to which it is bound, is a leaving group; and Y₆ is H or ahydroxyl protecting group or Y₆, together with the oxygen atom to whichit is bound, is a leaving group, provided that when Q is —(CH₂)₃OY₁, Uis —OY₆, wherein —OY₆ is a leaving group, and Y₁, Y₃, and Y₄ areprotecting groups, Y₅ is not H. Exemplary compounds have the formula(IIIa):

In particular embodiments, Q is —(CH₂)₃OY₁. In these embodiments, Y₁,together with the oxygen atom to which it is bound, is, for example, anester, carbonate, carbamate, sulfonate, or ether hydroxyl protectinggroup; each of Y₃ and Y₄ is, for example, independently and togetherwith the oxygen atom to which it is bound, an ester, carbonate,carbamate, sulfonate, or ether hydroxyl protecting group, or Y₃ and Y₄together with the oxygen atoms to which they are bound are, for example,a cyclic carbonate, cyclic boronate, acetal, ketal, or cyclic silylenehydroxyl protecting group or 1,1,3,3-tetraisopropylsiloxanediyl; and/orY₅, together with the oxygen atom to which it is bound, is, for example,an ester, carbonate, carbamate, sulfonate, or ether hydroxyl protectinggroup. In specific examples, Y₁ is pivaloyl, acetyl, benzoyl,p-bromobenzoyl, p-methoxybenzoyl, 1-naphthoyl, 2-naphthoyl, o-phthaloyl,benzyl, p-methoxybenzyl, triphenylmethyl, tri(C1-C6 alkyl)silyl,tri(C6-C10 aryl or C1-C6 heteroaryl)silyl, di(C6-C10 aryl or C1-C6heteroaryl)(C1-C6 alkyl)silyl, or (C6-C10 aryl or C1-C6heteroaryl)di(C1-C6 alkyl)silyl; Y₃ and Y₄ are each independentlytri(C1-C6 alkyl)silyl, tri(C6-C10 aryl or C1-C6 heteroaryl)silyl,di(C6-C10 aryl or C1-C6 heteroaryl)(C1-C6 alkyl)silyl, or (C6-C10 arylor C1-C6 heteroaryl)di(C1-C6 alkyl)silyl, or Y₃ and Y₄ are togetherdi(C1-C6)alkylsilylene; and/or Y₅ is acetyl, benzoyl, p-bromobenzoyl,p-methoxybenzoyl, 1-naphthoyl, 2-naphthoyl, or o-phthaloyl.

In other embodiments, Y₅ is H or a hydroxyl protecting group; Y₆ is H;or —OY₆ is a leaving group, such as (C1-C6)alkylsulfonate, (C6-C10 arylor C1-C6 heteroaryl)sulfonate, (C6-C15)aryl(C1-C6)alkylsulfonate, or(C1-C6)heteroaryl(C1-C6)alkylsulfonate. Specific leaving groups includemesylate, toluenesulfonate, isopropylsulfonate, phenylsulfonate, orbenzylsulfonate.

A specific example has the formula:

Additional compounds of the invention are described herein.

The invention further features use of the compounds of the invention,e.g., Compounds E-AM, in the manufacture of ER-804028 and analogs ofhalichondrin B, such as eribulin, or a pharmaceutically acceptable saltthereof, e.g., eribulin mesylate.

In one aspect, the invention features a method of synthesizing ER-804028by (i) reacting a compound having the formula (I):

with a compound having the formula (IV):

wherein Y₃, and Y₄, are each independently H or a hydroxyl protectinggroup, under Nozaki-Hiyama-Kishi (NHK) coupling conditions to produce acompound of formula (II):

(ii) reacting the product of step (i) under Vasella fragmentationconditions to produce a compound of formula (III):

(iii) reacting the product of step (ii) under conditions forintramolecular Williamson etherification to produce ER-804028:

Asymmetric or chiral centers exist in the compounds of the invention.The present invention includes the various stereoisomers of thecompounds and mixtures thereof, unless otherwise specified. Individualstereoisomers of the compounds of the present invention are preparedsynthetically from commercially available starting materials thatcontain asymmetric or chiral centers or by preparation of mixtures ofcompounds followed by resolution as is well known in the art. Thesemethods of resolution are exemplified by direct separation of themixture of diastereomers on chiral chromatographic columns or by chiralHPLC methods. Methods of chiral separation have been describedpreviously (GB. Cox (ed.) in Preparative EnantioselectiveChromatography, 2005, Blackwell Publishing). Alternatively, chiralcompounds can be prepared by an asymmetric synthesis that favors thepreparation of one diastereomer over another. Geometric isomers may alsoexist in the compounds of the present invention. The present inventionincludes the various geometric isomers and mixtures thereof resultingfrom the arrangement of substituents around a carbon-carbon double bond,such as isomers of the Z or E configuration. It is also recognized thatfor structures in which tautomeric forms are possible, the descriptionof one tautomeric form is equivalent to the description of both, unlessotherwise specified. In certain embodiments, a diastereomer of acompound of the invention is present in a mixture at a ratio of 10:1,20:1, 30:1, 50:1, or greater as compared to other diastereomers.

Compounds useful in the invention may be isotopically labeled compounds.Useful isotopes include hydrogen, carbon, nitrogen, and oxygen (e.g.,²H, ³H, ¹³C, ¹⁴C, ⁵N, ⁸O, and ¹⁷O). Isotopically-labeled compounds canbe prepared by synthesizing a compound using a readily availableisotopically-labeled reagent in place of a non-isotopically-labeledreagent.

For any of the following chemical definitions, a number following anatomic symbol indicates that total number of atoms of that element thatare present in a particular chemical moiety. As will be understood,other atoms, such as hydrogen atoms, or substituent groups, as describedherein, may be present, as necessary, to satisfy the valences of theatoms. For example, an unsubstituted C2 alkyl group has the formula—CH₂CH₃. When used with the groups defined herein, a reference to thenumber of carbon atoms includes the divalent carbon in acetal and ketalgroups but does not include the carbonyl carbon in acyl, ester,carbonate, or carbamate groups. A reference to the number of oxygen,nitrogen, or sulfur atoms in a heteroaryl group only includes thoseatoms that form a part of a heterocyclic ring.

By “acetal” is meant >CHR (or —CHR—), wherein R is H, alkyl, alkenyl,aryl, or arylalkyl.

By “acyl” is meant —C(O)R, wherein R is H, alkyl, alkenyl, aryl, orarylalkyl. In exemplary acyl groups, R is H, C1-C12 alkyl (e.g., C1-C8,C1-C6, C1-C4, C2-C7, C3-C12, and C3-C6 alkyl), C2-C12 alkenyl (e.g.,C2-C8, C2-C6, C2-C4, C3-C12, and C3-C6 alkenyl), C6-C20 aryl (e.g.,C6-C15, C6-C10, C8-C20, and C8-C15 aryl), monocyclic C1-C6 heteroaryl(e.g., monocyclic C1-C4 and C2-C6 heteroaryl), C4-C19 heteroaryl (e.g.,C4-C10 heteroaryl), (C6-C15)aryl(C1-C6)alkyl,(C1-C6)heteroaryl(C1-C6)alkyl, or (C4-C19)heteroaryl(C1-C6)alkyl. Asdefined herein, any heteroaryl group present in an acyl group has from 1to 4 heteroatoms selected independently from O, N, and S.

By “alkyl” is meant a straight or branched chain saturated cyclic (i.e.,cycloalkyl) or acyclic hydrocarbon group of from 1 to 12 carbons, unlessotherwise specified. Exemplary alkyl groups include C1-C8, C1-C6, C1-C4,C2-C7, C3-C12, and C3-C6 alkyl. Specific examples include methyl, ethyl,1-propyl, 2-propyl, 2-methyl-1-propyl, 1-butyl, 2-butyl, and the like.Unless otherwise noted, alkyl groups, used in any context herein, areoptionally substituted with halogen, alkoxy, aryloxy, arylalkyloxy, oxo,alkylthio, alkylenedithio, alkylamino, [alkenyl]alkylamino,[aryl]alkylamino, [arylalkyl]alkylamino, dialkylamino, silyl, sulfonyl,cyano, nitro, carboxyl, or azido.

By “alkylamino” is meant —NHR, wherein R is alkyl. By“[alkenyl]alkylamino” is meant —NRR′, wherein R is alkyl, and R′ isalkenyl. By “[aryl]alkylamino” is meant —NRR′, wherein R is alkyl, andR′ is aryl. By “[arylalkyl]alkylamino” is meant —NRR′, wherein R isalkyl, and R′ is arylalkyl. By “dialkylamino” is meant —NR₂, whereineach R is alkyl, selected independently.

By “alkylene” is meant a divalent alkyl group. Alkylene groups, used inany context herein, are optionally substituted in the same manner asalkyl groups. For example, a C1 alkylene group is —CH₂—.

By “alkylenedithio” is meant —S-alkylene-S—.

By “alkylthio” is meant —SR, wherein R is alkyl.

By “alkenyl” is meant a straight or branched chain cyclic or acyclichydrocarbon group of, unless otherwise specified, from 2 to 12 carbonsand containing one or more carbon-carbon double bonds. Exemplary alkenylgroups include C2-C8, C2-C7, C2-C6, C2-C4, C3-C12, and C3-C6 alkenyl.Specific examples include ethenyl (i.e., vinyl), 1-propenyl, 2-propenyl(i.e., allyl), 2-methyl-1-propenyl, 1-butenyl, 2-butenyl (i.e., crotyl),and the like. Alkenyl groups, used in any context herein, are optionallysubstituted in the same manner as alkyl groups. Alkenyl groups, used inany context herein, may also be substituted with an aryl group.

By “alkoxy” is meant —OR, wherein R is alkyl.

By “aryl” is meant a monocyclic or multicyclic ring system having one ormore aromatic rings, wherein the ring system is carbocyclic orheterocyclic. Heterocyclic aryl groups are also referred to asheteroaryl groups. A heteroaryl group includes 1 to 4 atoms selectedindependently from O, N, and S. Exemplary carbocyclic aryl groupsinclude C6-C20, C6-C15, C6-C10, C8-C20, and C8-C15 aryl. A preferredaryl group is a C6-10 aryl group. Specific examples of carbocyclic arylgroups include phenyl, indanyl, indenyl, naphthyl, phenanthryl,anthracyl, and fluorenyl. Exemplary heteroaryl groups include monocylicrings having from 1 to 4 heteroatoms selected independently from O, N,and S and from 1 to 6 carbons (e.g., C1-C6, C1-C4, and C2-C6).Monocyclic heteroaryl groups preferably include from 5 to 9 ringmembers. Other heteroaryl groups preferably include from 4 to 19 carbonatoms (e.g., C4-C10). Specific examples of heteroaryl groups includepyridinyl, quinolinyl, dihydroquinolinyl, isoquinolinyl, quinazolinyl,dihydroquinazolyl, and tetrahydroquinazolyl. Unless otherwise specified,aryl groups, used in any context herein, are optionally substituted withalkyl, alkenyl, aryl, arylalkyl, halogen, alkoxy, aryloxy, arylalkyloxy,oxo, alkylthio, alkylenedithio, alkylamino, [alkenyl]alkylamino,[aryl]alkylamino, [arylalkyl]alkylamino, dialkylamino, silyl, sulfonyl,cyano, nitro, carboxyl, or azido.

By “arylalkyl” is meant —R′R″, wherein R′ is alkylene, and R″ is aryl.

By “arylalkyloxy” is meant —OR, wherein R is arylalkyl.

By “aryloxy” is meant —OR, wherein R is aryl.

By “carbamate” is meant —OC(O)NR₂, wherein each R is independently H,alkyl, alkenyl, aryl, or arylalkyl.

By “carbonate” is meant —OC(O)OR, wherein R is alkyl, alkenyl, aryl, orarylalkyl.

By “carboxyl” is meant —C(O)OH, in free acid, ionized, or salt form.

By “cyclic boronate” is meant —OBRO—, wherein R is alkyl, alkenyl, aryl,arylalkyl, alkoxy, or 2,6-diacetamidophenyl.

By “cyclic carbonate” is meant —OC(O)O—.

By “cyclic silylene” is meant —OSiR₂O—, wherein each R is independentlyalkyl, alkenyl, aryl, arylalkyl, or alkoxy. By “dialkylsilylene” ismeant a cyclic silylene, wherein each R is alkyl.

By “ester” is meant —OC(O)R, where —C(O)R is an acyl group, as definedherein, that is bound to the oxygen atom of a protected hydroxyl, asdefined below.

By “ether” is meant —OR, wherein R is alkyl, alkenyl, arylalkyl, silyl,or 2-tetrahydropyranyl.

By “halogen” is meant fluoro, chloro, bromo, or iodo.

By “ketal” is meant >CR₂ (or —CR₂—), wherein each R is independentlyalkyl, alkenyl, aryl, or arylalkyl, or both R groups are togetheralkylene.

By “oxo” or (O) is meant ═O.

By “silyl” is meant —SiR₃, wherein each R is independently alkyl,alkenyl, aryl, or arylalkyl. Examples of silyl groups include tri(C1-C6alkyl)silyl, tri(C6-C10 aryl or C1-C6 heteroaryl)silyl, di(C6-C10 arylor C1-C6 heteroaryl)(C1-C6 alkyl)silyl, and (C6-C10 aryl or C1-C6heteroaryl)di(C1-C6 alkyl)silyl. It will be understood that, when asilyl group includes two or more alkyl, alkenyl, aryl, heteroaryl, orarylalkyl groups, these groups are independently selected. As definedherein, any heteroaryl group present in a silyl group has from 1 to 4heteroatoms selected independently from O, N, and S.

By “sulfonate” is meant —OS(O)₂R, wherein R is alkyl, alkenyl, aryl, orarylalkyl. In exemplary sulfonates, R is C1-C12 alkyl (e.g., C1-C8,C1-C6, C1-C4, C2-C7, C3-C12, and C3-C6 alkyl), C2-C12 alkenyl (e.g.,C2-C8, C2-C6, C2-C4, C3-C12, and C3-C6 alkenyl), carbocyclic C6-C20 aryl(e.g., C6-C15, C6-C10, C8-C20, and C8-C15 aryl), monocyclic C1-C6heteroaryl (e.g., C1-C4 and C2-C6 heteroaryl), C4-C19 heteroaryl (e.g.,C4-C10 heteroaryl), (C6-C15)aryl(C1-C6)alkyl,(C4-C19)heteroaryl(C1-C6)alkyl, or (C1-C6)heteroaryl(C1-C6)alkyl. Asdefined herein, any heteroaryl group present in a sulfonate group hasfrom 1 to 4 heteroatoms selected independently from O, N, and S.

By “sulfonyl” is meant —S(O)₂R, wherein R is alkyl, alkenyl, aryl,arylalkyl, or silyl. Preferred R groups for sulfonyl are the same asthose described above for sulfonates.

By “hydroxyl protecting group” is meant any group capable of protectingthe oxygen atom to which it is attached from reacting or bonding.Hydroxyl protecting groups are known in the art, e.g., as described inWuts, Greene's Protective Groups in Organic Synthesis,Wiley-Interscience, 4^(th) Edition, 2006. Exemplary protecting groups(with the oxygen atom to which they are attached) are independentlyselected from esters, carbonates, carbamates, sulfonates, and ethers.

In exemplary ester hydroxyl protecting groups, R of the acyl group isC1-C12 alkyl (e.g., C1-C8, C1-C6, C1-C4, C2-C7, C3-C12, and C3-C6alkyl), C2-C12 alkenyl (e.g., C2-C8, C2-C6, C2-C4, C3-C12, and C3-C6alkenyl), carbocyclic C6-C20 aryl (e.g., C6-C15, C6-C10, C8-C20, andC8-C15 aryl), monocyclic C1-C6 heteroaryl (e.g., C1-C4 and C2-C6heteroaryl), C4-C19 heteroaryl (e.g., C4-C10 heteroaryl),(C6-C15)aryl(C1-C6)alkyl, (C4-C19)heteroaryl(C1-C6)alkyl, or(C1-C6)heteroaryl(C1-C6)alkyl. Specific examples of acyl groups for usein esters include formyl, benzoylformyl, acetyl (e.g., unsubstituted orchloroacetyl, trifluoroacetyl, methoxyacetyl, triphenylmethoxyacetyl,and p-chlorophenoxyacetyl), 3-phenylpropionyl, 4-oxopentanoyl,4,4-(ethylenedithio)pentanoyl, pivaloyl (Piv), vinylpivaloyl, crotonoyl,4-methoxy-crotonoyl, naphthoyl (e.g., 1- or 2-naphthoyl), and benzoyl(e.g., unsubstituted or substituted, e.g., p-methoxybenzoyl, phthaloyl(including salts, such a triethylamine and potassium), p-bromobenzoyl,and 2,4,6-trimethylbenzoyl). As defined herein, any heteroaryl grouppresent in an ester group has from 1 to 4 heteroatoms selectedindependently from O, N, and S.

In exemplary carbonate hydroxyl protecting groups, R is C1-C12 alkyl(e.g., C1-C8, C1-C6, C1-C4, C2-C7, C3-C12, and C3-C6 alkyl), C2-C12alkenyl (e.g., C2-C8, C2-C6, C2-C4, C3-C12, and C3-C6 alkenyl),carbocyclic C6-C20 aryl (e.g., C6-C15, C6-C10, C8-C20, and C8-C15 aryl),monocyclic C1-C6 heteroaryl (e.g., C1-C4 and C2-C6 heteroaryl), C4-C19heteroaryl (e.g., C4-C10 heteroaryl), (C6-C15)aryl(C1-C6)alkyl,(C4-C19)heteroaryl(C1-C6)alkyl, or (C1-C6)heteroaryl(C1-C6)alkyl.Specific examples include methyl, 9-fluorenylmethyl, ethyl,2,2,2-trichloroethyl, 2-(trimethylsilyl)ethyl, 2-(phenylsulfonyl)ethyl,vinyl, allyl, t-butyl, p-nitrobenzyl, and benzyl carbonates. As definedherein, any heteroaryl group present in a carbonate group has from 1 to4 heteroatoms selected independently from O, N, and S.

In exemplary carbamate hydroxyl protecting groups, each R isindependently H, C1-C12 alkyl (e.g., C1-C8, C1-C6, C1-C4, C2-C7, C3-C12,and C3-C6 alkyl), C2-C12 alkenyl (e.g., C2-C8, C2-C6, C2-C4, C3-C12, andC3-C6 alkenyl), carbocyclic C6-C20 aryl (e.g., C6-C15, C6-C10, C8-C20,and C8-C15 aryl), monocyclic C1-C6 heteroaryl (e.g., C1-C4 and C2-C6heteroaryl), C4-C19 heteroaryl (e.g., C4-C10 heteroaryl),(C6-C15)aryl(C1-C6)alkyl, (C4-C19)heteroaryl(C1-C6)alkyl, or(C1-C6)heteroaryl(C1-C6)alkyl. Specific examples include N-phenyl andN-methyl-N-(o-nitrophenyl) carbamates. As defined herein, any heteroarylgroup present in a carbamate group has from 1 to 4 heteroatoms selectedindependently from O, N, and S.

Exemplary ether hydroxyl protecting groups include C1-C12 alkylethers(e.g., C1-C8, C1-C6, C1-C4, C2-C7, C3-C12, and C3-C6 alkyl), C2-C12alkenylethers (e.g., C2-C8, C2-C6, C2-C4, C3-C12, and C3-C6 alkenyl),(C6-C15)aryl(C1-C6)alkylethers, (C4-C19)heteroaryl(C1-C6)alkylethers,(C1-C6)heteroaryl(C1-C6)alkylethers, (C1-C6)alkoxy(C1-C6)alkylethers,(C1-C6)alkylthio(C1-C6)alkylethers,(C6-C10)aryl(C1-C6)alkoxy(C1-C6)alkylethers, and silylethers (e.g.,tri(C1-C6 alkyl)silyl, tri(C6-C10 aryl or C1-C6 heteroaryl)silyl,di(C6-C10 aryl or C1-C6 heteroaryl)(C1-C6 alkyl)silyl, and (C6-C10 arylor C1-C6 heteroaryl)di(C1-C6 alkyl)silyl). Specific examples ofalkylethers include methyl and t-butyl, and an example of an alkenylether is allyl. Examples of alkoxyalkylethers and alkylthioalkylethersinclude methoxymethyl, methylthiomethyl, (2-methoxyethoxy)methyl, andβ-(trimethylsilyl)ethoxymethyl. Examples of arylalkylethers includebenzyl, p-methoxybenzyl (MPM), 3,4-dimethoxybenzyl, triphenylmethyl(trityl), o-nitrobenzyl, p-nitrobenzyl, p-halobenzyl,2,6-dichlorobenzyl, p-cyanobenzyl, naphthylmethyl, and 2- and 4-picolylethers. Specific examples of silylethers include trimethylsilyl (TMS),triethylsilyl (TES), t-butyldimethylsilyl (TBS), t-butyldiphenylsilyl(TBDPS), triisopropylsilyl (TIPS), and triphenylsilyl (TPS) ethers. Anexample of an arylalkyloxyalkylether is benzyloxymethyl ether. Asdefined herein, any heteroaryl group present in an ether group has from1 to 4 heteroatoms selected independently from O, N, and S.

Adjacent hydroxyl groups may be protected with a diol protecting group,such as acetal (e.g., C1-C6 alkyl), ketal (e.g., C2-C6 alkyl or C3-C6cycloalkyl), cyclic silylene, cyclic carbonate, and cyclic boronate.Examples of acetal and ketal groups include methylene, ethylidene,benzylidene, isopropylidene, cyclohexylidene, and cyclopentylidene. Anexample of a cyclic silylene is di-t-butylsilylene. Another diolprotecting group is 1,1,3,3-tetraisopropylsiloxanediyl. Examples ofcyclic boronates include methyl, ethyl, phenyl, and2,6-diacetamidophenyl boronates.

Protecting groups may be substituted as is known in the art; forexample, aryl and arylalkyl groups, such as phenyl, benzyl, naphthyl, orpyridinyl, can be substituted with C1-C6 alkyl, C1-C6 alkoxy, nitro,cyano, carboxyl, or halogen. Alkyl groups, such as methyl, ethyl,isopropyl, n-propyl, t-butyl, n-butyl, and sec-butyl, and alkenylgroups, such as vinyl and allyl, can also be substituted with oxo,arylsulfonyl, halogen, and trialkylsilyl groups. Preferred protectinggroups are TBS and Piv. Protecting groups that are orthogonal areremoved under different conditions, as in known in the art.

By “leaving group” is meant a group that is displaced during a chemicalreaction. Suitable leaving groups are well known in the art, e.g., see,Advanced Organic Chemistry, March, 4th Ed., pp. 351-357, John Wiley andSons, N.Y. (1992). Such leaving groups include halogen, C1-C12 alkoxy(e.g., C1-C8, C1-C6, C1-C4, C2-C7, and C3-C6 alkoxy), C1-C12alkylsulfonate (e.g., C1-C8, C1-C6, C1-C4, C2-C7, C3-C12, and C3-C6alkylsulfonate), C2-C12 alkenylsulfonate (e.g., C2-C8, C2-C6, C2-C4,C3-C12, and C3-C6 alkenylsulfonate), carbocyclic C6-C20 arylsulfonate(e.g., C6-C15, C6-C10, C8-C20, and C8-C15 arylsulfonate), C4-C19heteroarylsulfonate (e.g., C4-C10 heteroarylsulfonate), monocyclic C1-C6heteroarylsulfonate (e.g., C1-C4 and C2-C6 heteroarylsulfonate),(C6-C15)aryl(C1-C6)alkylsulfonate,(C4-C19)heteroaryl(C1-C6)alkylsulfonate,(C1-C6)heteroaryl(C1-C6)alkylsulfonate, and diazonium. Alkylsulfonates,alkenylsulfonates, arylsulfonates, heteroarylsulfonates,arylalkylsulfonates, and heteroarylalkylsulfonates can be optionallysubstituted with halogen (e.g., chloro, iodo, bromo, or fluoro), alkoxy(e.g., C1-C6 alkoxy), aryloxy (e.g., C6-C15 aryloxy, C4-C19heteroaryloxy, and C1-C6 heteroaryloxy), oxo, alkylthio (e.g., C1-C6alkylthio), alkylenedithio (e.g., C1-C6 alkylenedithio), alkylamino(e.g., C1-C6 alkylamino), [alkenyl]alkylamino (e.g.,[(C2-C6)alkenyl](C1-C6)alkylamino), [aryl]alkylamino (e.g.,[(C6-C10)aryl](C1-C6)alkylamino, [(C1-C6)heteroaryl] (C1-C6)alkylamino,and [(C4-C19)heteroaryl](C1-C6)alkylamino), [arylalkyl] alkylamino(e.g., [(C6-C10)aryl(C1-C6)alkyl] (C1-C6)alkylamino,[(C1-C6)heteroaryl(C1-C6)alkyl](C1-C6)alkylamino, and[(C4-C19)heteroaryl(C1-C6)alkyl](C1-C6)alkylamino), dialkylamino (e.g.,di(C1-C6 alkyl)amino), silyl (e.g., tri(C1-C6 alkyl)silyl, tri(C6-C10aryl or C1-C6 heteroaryl)silyl, di(C6-C10 aryl or C1-C6heteroaryl)(C1-C6 alkyl)silyl, and (C6-C10 aryl or C1-C6heteroaryl)di(C1-C6 alkyl)silyl), cyano, nitro, or azido.Alkenylsulfonates can be optionally substituted with carbocyclic aryl(e.g., C6-C15 aryl), monocyclic C1-C6 heteroaryl, or C4-C19 heteroaryl(e.g., C4-C10 heteroaryl). Arylsulfonates can be optionally substitutedwith alkyl (e.g., C1-C6 alkyl) or alkenyl (e.g. C2-C6 alkenyl). Asdefined herein, any heteroaryl group present in a leaving group has from1 to 4 heteroatoms selected independently from O, N, and S.

Specific examples of suitable leaving groups include chloro, iodo,bromo, fluoro, methanesulfonate (mesylate), 4-toluenesulfonate(tosylate), trifluoromethanesulfonate (triflate, OTf),nitro-phenylsulfonate (nosylate), and bromo-phenylsulfonate (brosylate).Leaving groups may also be further substituted as is known in the art.

By “pharmaceutically acceptable salt” is meant a salt within the scopeof sound medical judgment, suitable for use in contact with the tissuesof humans and animals without undue toxicity, irritation, allergicresponse and the like and commensurate with a reasonable benefit/riskratio. Pharmaceutically acceptable salts are well known in the art. Forexample, pharmaceutically acceptable salts are described in: Berge etal., J. Pharmaceutical Sciences 66:1-19, 1977 and in PharmaceuticalSalts: Properties, Selection, and Use, (Eds. P. H. Stahl and C. G.Wermuth), Wiley-VCH, 2008. Representative acid addition salts includeacetate, adipate, alginate, ascorbate, aspartate, benzenesulfonate,benzoate, bisulfate, borate, butyrate, camphorate, camphorsulfonate,citrate, cyclopentanepropionate, digluconate, dodecylsulfate,ethanesulfonate, fumarate, glucoheptonate, glycerophosphate,hemisulfate, heptonate, hexanoate, hydrobromide, hydrochloride,hydroiodide, 2-hydroxy-ethanesulfonate, lactobionate, lactate, laurate,lauryl sulfate, malate, maleate, malonate, methanesulfonate,2-naphthalenesulfonate, nicotinate, nitrate, oleate, oxalate, palmitate,pamoate, pectinate, persulfate, 3-phenylpropionate, phosphate, picrate,pivalate, propionate, stearate, succinate, sulfate, tartrate,thiocyanate, toluenesulfonate, undecanoate, valerate salts and the like.A preferred salt is the mesylate salt.

Other features and advantages of the invention will be apparent from thefollowing description and the claims.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides compounds and methods of their use in thesynthesis of halichondrin B analogs. In particular, the compounds areuseful for the synthesis of the C14-C35 portion of halichondrin Banalogs. ER-804028 is a C14-C35 fragment that has been employed in thesynthesis of eribulin:

Halichondrin B analogs, e.g., eribulin or pharmaceutically acceptablesalts thereof, can be synthesized from the C14-C35 fragment as describedin U.S. Pat. No. 6,214,865 and International Publication No. WO2005/118565. In one example described in these references, the C14-C35portion, e.g., ER-804028, of the molecule is coupled to the C1-C13portion, e.g., ER-803896, to produce ER-804029, and additional reactionsare carried out to produce eribulin (Scheme 1):

Lithiation of the C14-C35 sulfone fragment followed by coupling to theC1-C13 aldehyde fragment furnishes a mixture of diastereomeric alcohols(ER-804029). Additional protecting group manipulation and oxidationfollowed by removal of the sulfonyl group and an intramolecularNozaki-Hiyama-Kishi (NHK) reaction affords an intermediate, which, whenoxidized and treated with tetrabutylammonium fluoride, undergoesintramolecular oxy-Michael ring closure. Pyridinium p-toluenesulfonatemediated ketal formation and conversion of the terminal alcohol to anamine furnishes eribulin.

For example, as described in WO 2005/118565 (Example 6), ER-804029 isreacted to produce ER-804030; ER-804030 is reacted to produce ER-118049;ER-118049 is reacted to produce mixture ER-118047/118048; the mixtureER-118047/118048 is reacted to produce ER-118046; ER-118046 is reactedto produce ER-811475; ER-811475 is reacted to produce ER-076349; andER-076349 is reacted to produce eribulin.

Pharmaceutically acceptable salts of eribulin, e.g., eribulin mesylate,can be formed by methods known in the art, e.g., in situ during thefinal isolation and purification of the compound or separately byreacting the free base group with a suitable organic acid. In oneexample, eribulin is treated with a solution of MsOH and NH₄OH in waterand acetonitrile. The mixture is concentrated. The residue is dissolvedin DCM-pentane, and the solution is added to anhydrous pentane. Theresulting precipitate is filtered and dried under high vacuum to provideeribulin mesylate, as shown in Scheme 2.

A scheme for producing one example of a C14-C35 fragment (ER-804028) isas follows (Scheme 3).

Generally, (−)-quinic acid is converted to Compound A through stages1-13 as described in International Publication Nos. WO 2009/046308 andWO 2005/118565. As outlined in Scheme 3, oxidation followed byHorner-Wadsworth-Emmons (HWE) reaction of the resulting lactol,hydrogenation, and protecting group modification furnishes Compounds Eand F Blaise reaction followed by methyl ketone formation, dehydration,enolization, triflation, desilylation, and iodination producesiodo-vinyl triflate, Compound O. NHK coupling of Compound O withER-806067 furnishes Compound P. Acetylation followed by Vasellafragmentation, intramolecular Williamson etherification, and protectinggroup modification affords C14-C35 fragment ER-804028. This scheme isadvantageous as it results in improved stereoselectivity at C27, i.e.,67:1 dr compared to 13:1 dr in previous processes. The scheme is alsoadvantageous as the C14-C26 starting material and C14-C35 product of theNHK coupling of this scheme exhibit greater stability than the startingmaterial and product of previous methods. The C14-C26 starting materialand C14-C35 product of the NHK coupling are stable indefinitely at roomtemperature, allowing for a flexible manufacturing schedule.

One skilled in the art would also understand that variations on theabove scheme are possible. For example, the hydroxyl protecting groupsemployed in particular reactions may be varied. In other variations, theleaving groups employed may be altered; for example, triflate groups canbe replaced with halogens such as iodine or bromine.

In addition, although the scheme depicts Compound C et seq. with carbonsC14-C16, the reactions leading to the addition of carbons C14 and C15can occur at any point prior to the synthesis of ER-804028. Syntheticsteps for adding carbons C14 and C15 are disclosed in WO 2009/046308. Inspecific examples, Compound A or Compound B can be altered as shown inScheme 4, and the products AG and AH substituted for Compound E or F inScheme 3.

In accordance with the synthetic scheme, the invention providescompounds having the formula:

e.g., Compound O, Compound AI, and Compound AJ, wherein X is halogen oroxo; Z is a leaving group; Q is —C(O)H, —CH═CHC(O)OY₁,—C(R)H(CH₂)_(n)OY₁, or —C(R)HCH₂C(O)OY₁; R is H or —OY₂; Y₁ and Y₂ areeach independently H or a hydroxyl protecting group; and n is 1 or 2.When both Y₁ and Y₂ are present, they may be the same or different. Inaddition, when Y₁ and Y₂ are on adjacent carbons, e.g., when n=1, theymay together form a divalent hydroxyl protecting group. Compounds ofthis formula include those having the formula:

wherein Y₁ is H, pivaloyl, benzoyl, p-bromobenzoyl, 1-naphthoyl,2-naphthoyl, p-methoxybenzoyl, or o-phthaloyl (including salts such astriethylamine and potassium).

The invention also provides compounds having the formula:

e.g., Compound P, Compound AD, Compound AF, Compound AK, Compound AL,and Compound AM, wherein X is halogen or oxo; Q is —C(O)H,—CH═CHC(O)OY₁, —C(R)H(CH₂)_(n)OY₁, or —C(R)HCH₂C(O)OY₁; R is H or —OY₂;n is 1 or 2; Y₁, Y₂, Y₃, and Y₄ are each independently H or a hydroxylprotecting group; T is oxo or —OY₅; and Y₅ is H or a hydroxyl protectinggroup, or Y₅, together with the oxygen atom to which it is bound, is aleaving group. In certain embodiments, Y₃ and Y₄ are together a divalenthydroxyl protecting group. In other embodiments, Y₁, Y₃, and Y₄ areprotecting groups, and Y₁ is orthogonal to Y₃ and Y₄. In furtherembodiments, Y₁, Y₃, Y₄, and Y₅ are protecting groups; Y₃ and Y₄ areorthogonal to Y₁ and Y₅; and Y₁ is orthogonal to Y₅. Compounds of thisformula include those having the formula:

wherein Y₁ and Y₅ are as follows:

Y₁ Y₅ H H benzoyl benzoyl p-bromobenzoyl p-bromobenzoyl pivaloyl Hpivaloyl acetyl pivaloyl benzoyl 2-naphthoyl H 2-naphthoyl 2-naphthoyl1-naphthoyl H 1-naphthoyl 1-naphthoyl p-methoxybenzoyl Hp-methoxybenzoyl p-methoxybenzoyl o-phthaloyl H o-phthaloyl,triethylamine H salt

The invention also features compounds having the formula:

e.g., Compound AE, wherein Q is —C(O)H, —CH═CHC(O)OY₁,—C(R)H(CH₂)_(n)OY₁, or —C(R)HCH₂C(O)OY₁; R is H or —OY₂; n is 1 or 2;Y₁, Y₂, Y₃, and Y₄ are each independently H or a hydroxyl protectinggroup; U is halogen or —OY₆; Y₅ is H or a hydroxyl protecting group orY₅, together with the oxygen atom to which it is bound, is a leavinggroup; and Y₆ is H or a hydroxyl protecting group or Y₆, together withthe oxygen atom to which it is bound, is a leaving group, provided thatwhen Q is —C(R)H(CH₂)_(n)OY₁ (e.g., —(CH₂)₃OY₁), U is —OY₆, —OY₆ is aleaving group, and Y₁, Y₃, and Y₄ are protecting groups, Y₅ is not H. Incertain embodiments, Y₃ and Y₄ are together a divalent hydroxylprotecting group. In other embodiments, Y₁, Y₃, and Y₄ are protectinggroups, and Y₁ is orthogonal to Y₃ and Y₄. In further embodiments, Y₁,Y₃, Y₄, and Y₅ are protecting groups; Y₃ and Y₄ are orthogonal to Y₁ andY₅; and Y₁ is orthogonal to Y₅.

As described herein, the compounds of the invention can be used in thesynthesis of ER-804028 and in turn eribulin, or a pharmaceuticallyacceptable salt thereof, e.g., eribulin mesylate.

Experimental Procedures Compound D

The synthesis of Compound D from (−)-quinic acid is described in WO2009/046308, which is hereby incorporated by reference.

Compound E

Compound D (3.05 g, 9.80 mmol, 1 eq) was dissolved in DMF (6.1 ml) at22° C., and imidazole (1.00 g, 14.7 mmol, 1.5 eq) was added. Uponcomplete dissolution of imidazole, the mixture was cooled to 0° C., andTBSCl (1.55 g, 10.3 mmol, 1.05 eq) was added. The mixture was stirred at0° C. for 1 h, allowed to warm to room temperature and stirred for anadditional 1 h. The reaction mixture was diluted with MTBE (37 ml) andwashed with water (30 ml). The organic layer was separated, furtherwashed with water (9.2 ml), and concentrated to give Compound S:

as colorless oil (4.43 g with residual solvents, theoretical 100% yieldassumed). The crude product was used for the next reaction withoutpurification. ¹H NMR (400 MHz, CDCl₃): δ 4.20 (1H, m), 3.91 (1H, m),3.85 (1H, m), 3.64 (3H, s), 3.50 (1H, d, J=10.8 Hz) 3.45 (1H, d, J=10.8Hz), 2.90 (1H, m), 2.39 (1H, m), 2.31 (1H, m), 2.22 (1H, dd, J=14.0 Hz,8.8 Hz), 1.77-1.90 (2H, m), 1.60-1.74 (4H, m), 1.51 (1H, m), 1.27 (3H,d, J=6.8 Hz), 1.26 (1H, m), 0.86 (9H, s), 0.02 (6H, s); and ¹³C NMR (100MHz, CDCl₃): δ 174.08, 122.93, 84.86, 75.78, 73.45, 66.82, 66.31, 51.77,41.04, 38.16, 31.44, 31.04, 26.20, 26.06 (3C), 22.51, 22.20, 18.51,18.48, −5.12, −5.17.

Compound S (4.2 g, 9.8 mmol, 1 eq) was dissolved in THF (21 ml) andcooled to 0° C. LiBH₄ (2.0 M solution in THF, 12.2 ml, 24.5 mmol, 2.5eq) was added, and the mixture was allowed to warm to 20° C. Stirringwas continued at 20-23° C. overnight (16 h). Another reactor was chargedwith 20 wt % citric acid (aqueous solution, 25 g, 26 mmol, 2.6 eq) andMTBE (40 ml), and the mixture was cooled to 0° C. The reaction mixturewas carefully/slowly poured into the pre-chilled citric acid-MTBE whilemaintaining T-internal <10° C. Upon complete addition, the mixture wasstirred at 0-5° C. for 30 min. The organic layer was separated,sequentially washed with: 1) saturated NaHCO₃ (12 g) and 2) 20 wt % NaCl(12 g), and concentrated to give crude Compound T:

as colorless oil (3.32 g, 8.3 mmol, 85% yield in 2 steps). ¹H NMR (400MHz, CDCl₃): δ 4.20 (1H, m), 3.93 (1H, dd, J=6.4 Hz, 4.8 Hz), 3.80 (1H,m), 3.57 (2H, m), 3.47 (1H, d, J=10.4 Hz), 3.42 (1H, d, J=10.4 Hz), 2.88(1H, m), 2.57 (1H, br), 2.18 (1H, dd, J=7.2 Hz, 14.4 Hz), 1.68-1.81 (2H,m), 1.45-1.68 (6H, m), 1.24 (3H, d, J=7.2 Hz), 1.22 (1H, m), 0.83 (9H,s), 0.02 (6H, s); and ¹³C NMR (100 MHz, CDCl₃): δ 122.90, 84.72, 76.75,73.56, 67.14, 66.53, 62.87, 40.94, 38.18, 33.58, 29.91, 26.36, 26.04,22.60, 22.48 (3C), 18.478, 18.43, −5.11, −5.16.

Compound T (2.30 g, 5.78 mmol, 1 eq) was dissolved in CH₂Cl₂ (12 ml).TEA (1.6 ml, 12 mmol, 2.0 eq) was added followed by DMAP (71 mg, 0.58mmol, 0.10 eq). The mixture was cooled to 0° C., and pivaloyl chloride(0.747 ml, 6.07 mmol, 1.05 eq) was added. The mixture was allowed towarm to 0° C., and stirring was continued at 20-22° C. for an additional2 h. The reaction mixture was diluted with MTBE (23 ml), sequentiallywashed with: 1) 20 wt % citric acid (aqueous solution, 12 g, 12 mmol,2.1 eq) and 2) saturated NaHCO₃ (aqueous solution, 4.6 g, 5.5 mmol, 0.95eq), and concentrated to give crude product as pale yellow oil. Thecrude was purified by Biotage (Uppsala, Sweden) 40M (heptane-MTBE 7:3v/v) to give Compound E as pale yellow oil (2.79 g, 5.04 mmol, 87%yield). ¹H NMR (400 MHz, CDCl₃): δ 4.22 (1H, m), 4.04 (1H, d, J=6.4 Hz),4.03 (1H, d, J=6.4 Hz), 4.93 (1H, dd, J=3.2 Hz, 6.4 Hz), 3.85 (1H, m),3.50 (1H, d, J=10.4 Hz), 3.45 (1H, d, J=10.4 Hz), 2.92 (1H, m), 2.21(1H, dd, J=8.4 Hz, 13.6 Hz), 1.48-1.85 (7H, m), 1.43 (1H, m), 1.29 (3H,d, J=7.6 Hz), 1.25 (1H, m), 1.17 (9H, s), 0.87 (9H, s), 0.02 (6H, s);and ¹³C NMR (100 MHz, CDCl₃): δ 178.78, 122.96, 84.83, 76.25, 73.45,67.11, 66.53, 64.43, 41.00, 38.94, 37.89, 32.98, 27.42 (3C), 26.47,26.06 (3C), 25.60, 22.60, 22.52, 18.51, 18.48, −5.09, −5.15.

Compound G

Zinc dust (876 mg, 13.4 mmol, 10.0 eq) was suspended in THF (3.9 ml).MsOH (0.0087 ml, 0.13 mmol, 0.10 eq) was added, and the mixture washeated at reflux for 20 min. A mixture of Compound E (0.645 g, 1.34mmol, 1 eq) and benzyl bromoacetate (0.315 ml, 2.01 mmol, 1.50 eq) inTHF (2.6 ml+1.3 ml) was added under reflux. After 2 h, benzylbromoacetate (0.10 ml, 0.67 mmol, 0.50 eq) was added, and heating wascontinued for an additional 3 h (total 5 h). After cooling down, thereaction mixture was diluted with MTBE (10 ml) and cooled to 5° C. 20 wt% citric acid (aqueous solution, 3.2 g, 3.4 mmol, 2.5 eq) was added, andvigorous stirring was continued at 5-10° C. for 10 min. The wholemixture was filtered through a pad of Celite (1.3 g). The organic layerwas separated and set aside. The aqueous layer was extracted with MTBE(10 ml). All organic layers were combined, sequentially washed with: 1)saturated NaHCO₃ (aqueous solution, 3.2 g) and 2) 20 wt % NaCl (aqueoussolution, 3.2 g), and concentrated to give crude product as yellow oil.The crude was purified by Biotage (Uppsala, Sweden) 25M (heptane-MTBE3:1 & 3:2 v/v) to give Compound G as pale yellow oil (0.627 g, 0.992mmol, 74% yield). ¹H NMR (400 MHz, CDCl₃): δ 7.95 (1H, br), 7.24-7.37(5H, m), 5.11 (1H, d, J=12.8 Hz), 5.07 (1H, d, J=12.8 Hz), 4.58 (1H, s),4.10 (1H, m), 4.02 (2H, m), 3.78 (1H, dd, J=5.6 Hz, 7.2 Hz), 3.56 (1H,m), 3.54 (1H, d, J=10.4 Hz), 3.46 (1H, d, J=10.4 Hz), 2.46 (1H, m), 2.15(1H, dd, J=8.8 Hz, 14.0 Hz), 1.35-1.82 (10H, m), 1.18 (1H, m), 1.17 (9H,s), 1.10 (3H, d, J=6.8 Hz), 0.88 (9H, s), 0.04 (6H, s); and ¹³C NMR (100MHz, CDCl₃): δ 178.77, 170.63, 168.91, 137.49, 128.66 (2C), 127.99 (2C),127.19, 84.27, 81.26, 75.91, 73.63, 67.52, 67.17, 64.71, 64.44, 42.75,38.94, 37.03, 35.46, 33.22, 27.43 (3C), 26.08, 26.01 (3C), 25.56, 23.50,20.06, 18.51, −5.09 (2C).

Compound L

Compound G (0.596 g, 0.943 mmol, 1 eq) was dissolved in THF (3.0ml)-water (1.0 ml) and cooled to 10° C. AcOH (2.0 ml, 35 mmol, 37 eq)was added, and the mixture was allowed to warm to room temperature.After 10 h, the reaction mixture was poured into a pre-chilled (0° C.)mixture of NaHCO₃ (4.8 g, 57 mmol, 60 eq), water (6 ml), and MTBE (20ml). The organic layer was separated, washed with water (6 ml), andconcentrated to give crude product. The crude was azeotroped withtoluene (20 ml) and purified by Biotage (Uppsala, Sweden) 25 M(heptane-EtOAc 9:1 v/v) to give Compound U:

(0.493 g, 0.779 mmol, 82% yield) as colorless oil.

An inert flask was charged with 10 wt % Pd—C(wet-type, 15 mg, 0.014mmol, 0.050 eq). A solution of Compound U (0.182 g, 0.288 mmol, 1 eq) inEtOAc (3.6 ml) was added under N₂. The internal atmosphere was replacedwith H₂, and stirring was continued at room temperature for 2 h. Themixture was filtered through a pad of Celite (1.0 g). The reactor andthe filter cake were rinsed with EtOAc (3.6 ml). The filtrate wasconcentrated to give crude keto-acid Compound J as colorless film. Aportion (10%) of crude Compound J was retained for analytical andstability testing. The remaining portion (90%) of Compound J wasdissolved in toluene (3.0 ml). The mixture was heated at 95° C. for 15min and then concentrated to give crude product as pale yellow oil. Thecrude was purified by Biotage (Uppsala, Sweden) 12M (heptane-EtOAc 95:5v/v) to give Compound L (110 mg, 0.220 mmol, 85% adjusted yield) ascolorless oil. ¹H NMR (400 MHz, CDCl₃): δ 4.08 (1H, m), 4.00 (1H, d,J=6.8 Hz), 3.98 (1H, d, J=6.8 Hz), 3.81 (1H, t, J=5.6 Hz), 3.49 (1H, m),3.44 (1H, d, J=10.4 Hz), 3.39 (1H, d, J=10.4 Hz), 2.73 (1H, m), 2.09(3H, s), 1.99 (1H, dd, J=8.8 Hz, 14.0 Hz), 1.32-1.75 (10H, m), 1.16 (1H,m), 1.13 (9H, s), 1.03 (3H, d, J=7.2 Hz), 0.84 (9H, s), 0.07 (6H, s);and ¹³C NMR (100 MHz, CDCl₃): δ 212.79, 178.68, 84.49, 76.05, 73.52,67.30, 66.67, 64.38, 43.45, 39.79, 39, 37.22, 32.98, 28.75, 27.37 (3C),26.91, 26.04 (3C), 25.53, 22.85, 18.47, 17.26, −5.15, −5.20.

Compound W

Compound L (109 mg, 0.218 mmol, 1 eq) was dissolved in THF (1.1 ml), andPhNTf₂ (117 mg, 0.328 mmol, 1.50 eq) was added. Upon completedissolution of PhNTf₂, the mixture was cooled to −30° C. 0.5 M KHMDS(solution in toluene, 0.590 ml, 0.295 mmol, 1.35 eq) was added, whilemaintaining T-internal <−25° C. Upon complete addition, stirring wascontinued at −25° C. for 1 h. 20 wt % NH₄Cl (aqueous solution, 0.33 g,12 mmol, 5.6 eq) was added while maintaining T-internal <−20° C., andthe resultant mixture was allowed to warm to 0° C. The mixture wasdiluted with water (0.33 g) and MTBE (2.2 ml) and then further stirredfor 5 min. The organic layer was separated, washed with saturated NaHCO₃(aqueous solution, 0.54 g), and concentrated to give crude Compound V:

Compound V was dissolved in MeOH (1.0 ml) and treated with 6 M HCl(solution in 2-propanol, 0.25 ml, 2 mmol, 7 eq) at 20° C. After 1 h, thereaction mixture was cooled to 0° C., neutralized with saturated NaHCO₃(1.6 g) and extracted with MTBE (6 ml). The organic layer was separated,washed with 20 wt % NaCl (0.54 g), and concentrated to give crudeproduct as pale yellow oil. The crude was purified by Biotage (Uppsala,Sweden) 12M (heptane-MTBE 1:1 & 3:7 v/v) to give Compound W (94.1 mg,0.182 mmol, 83% yield) as colorless oil. ¹H NMR (400 MHz, CDCl₃): δ 5.09(1H, d, J=3.6 Hz), 4.87 (1H, d, J=3.6 Hz), 4.12 (1H, m), 4.03 (1H, m),3.84 (1H, dd, J=6.4 Hz, 8.8 Hz), 3.59 (1H, m), 3.49 (1H, d, J=11.2 Hz),3.45 (1H, d, J=11.2 Hz), 2.68 (1H, m), 2.19 (1H, dd, J=8.8 Hz, 14.0 Hz),2.13 (1H, br), 1.87 (1H, m), 1.40-1.75 (8H, m), 1.35 (1H, dd, J=5.6 Hz,14.0 Hz), 1.20 (1H, m), 1.16 (9H, s), 1.13 (3H, d, J=6.8 Hz); and ¹³CNMR (100 MHz, CDCl₃): δ 178.75, 160.06, 120.20, 103.03, 83.76, 75.16,73.41, 68.59, 67.83, 64.25, 40.08, 38.94, 35.47, 35.21, 33.36, 28.05,27.39 (3C), 25.51, 24.55, 18.90.

Compound O

Compound W (90.0 mg, 0.174 mmol, 1 eq) was dissolved in CH₂Cl₂ andcooled to −10° C. Pyridine (0.042 ml, 0.52 mmol, 3.0 eq) was added,followed by Tf₂O (0.044 ml, 0.26 mmol, 1.5 eq) (T-internal <−3° C.).After stirring at −5 to 0° C. for 1 h, DMF (0.45 ml) was added, followedby NaI (78 mg, 0.52 mmol, 3.0 eq). Stirring was continued at 20-22° C.for 3 h, and then the reaction mixture was poured into a pre-chilled (0°C.) mixture of MTBE (2.0 ml) and water (2.0 ml). The organic layer wasseparated and set aside. The aqueous layer was extracted with MTBE (2.0ml). All organic layers were combined, washed with a mixture of water(0.4 ml) and 10 wt % Na₂SO₃ (0.9 g), and concentrate to give crudeproduct as yellow oil. The crude was purified by Biotage (Uppsala,Sweden) 12M (heptane-MTBE 85:15 v/v) to give Compound O (95.6 mg, 0.153mmol, 87% yield from Compound W) as colorless oil. ¹H NMR (400 MHz,CDCl₃): δ 5.08 (1H, d, J=3.6 Hz), 5.01 (1H, d, J=3.6 Hz), 4.18 (1H, m),4.05 (2H, m), 3.74 (1H, dd, J=6.4 Hz, 9.2 Hz), 3.53 (1H, m), 3.44 (1H,dd, J=1.2 Hz, 10.0 Hz), 3.37 (1H, d, J=10.0 Hz), 2.84 (1H, m), 2.32 (1H,dd, J=8.8 Hz, 14.0 Hz), 1.85 (1H, m), 1.44-1.76 (9H, m), 1.22 (1H, m),1.17 (9H, s), 1.13 (3H, d, J=6.8 Hz); and ¹³C NMR (100 MHz, CDCl₃): δ178.75, 159.70, 120.20, 103.21, 81.42, 76.18, 75.51, 68.06, 64.18,39.71, 38.96, 37.69, 35.43, 33.40, 27.94, 27.42 (3C), 25.51, 25.10,20.10, 18.72.

Compound P

A solution of ER-807363:

(ER-807363) (4.10 g, 13.8 mmol, 3.55 eq; WO 2005/118565) in THF (34.2ml) was purged with N₂ for 1 h, and CrCl₂ (1.70 g, 13.8 mmol, 3.55 eq)was added under N₂. The mixture was heated to 35° C., and TEA (1.93 ml,13.8 mmol, 3.55 eq) was added while maintaining T-internal <38° C. Themixture was heated at 30-35° C. for 1 h and cooled to 0° C. NiCl₂ (75.7mg, 0.15 eq) was added, and the mixture was purged with N₂ for 3 min. Apreviously degassed mixture of Compound 0 (2.44 g, 3.89 mmol, 1 eq), andER-806067:

(ER-806067) (2.57 g, 4.28 mmol, 1.10 eq; WO 2005/118565) in THF (17 ml)was added. The reaction was allowed to warm to 22° C. over 30 min, andstirring was continued at 22-24° C. for 20 h. The reaction mixture wascooled to 0° C. and diluted with heptane (70 ml). A solution ofethylenediamine (2.1 ml, 31 mmol, 8.0 eq) in water (12 ml) was addedwhile maintaining T-internal <5° C. The resultant mixture was vigorouslystirred at 0° C. for 1 h and filtered through a pad of Celite (2.4 g,rinsed with 12 ml heptane). The organic layer was separated, washed withwater (12 ml), and concentrated to give a green solid-oil, which wassuspended in heptane (20 ml), filtered for removal of ER-807363, andre-concentrated to give crude product. The crude was purified by Biotage(Uppsala, Sweden) 25M (heptane-MTBE 2:1 & 1:1) to give Compound P (2.64g, 2.44 mmol, 62% yield; C27-dr 67:1) as pale yellow oil. ¹H NMR (400MHz, CDCl₃): δ 7.88 (2H, m), 7.64 (1H, m), 7.57 (2H, m), 5.17 (1H, s),4.84 (1H, s), 4.12 (2H, m), 4.00 (2H, m), 3.91 (1H, m), 3.72 (4H, m),3.53 (1H, dd, J=5.6 Hz, 10.0 Hz), 3.30-3.50 (4H, m), 3.35 (3H, s), 3.06(2H, m), 2.55 (1H, m), 2.34 (1H, dd, J=8.8 Hz, 13.6 Hz), 2.28 (1H, m),1.97 (1H, m), 1.88 (1H, m), 1.40-1.83 (13H, m), 1.14 (9H, s), 1.03 (3H,d, J=6.8 Hz), 0.85 (18H, s), 0.05 (6H, s), 0.01 (6H, s); and ¹³C NMR(100 MHz, CDCl₃): δ 178.71, 156.78, 139.72, 134.26, 129.74 (2C), 128.06(2C), 107.98, 85.78, 83.71, 81.19, 79.09, 76.36, 75.43, 73.77, 71.33,68.86, 67.95, 64.22, 58.35, 57.65, 44.46, 44.31, 41.51, 38.92, 37.39,33.60, 33.40, 32.31, 28.30, 27.43, 27.19, 26.20 (6C), 26.15 (3C), 25.50,25.20, 22.65, 20.84, 18.58, 18.37, −3.89, −4.49, −5.10 (2C).

Compound AF

Compound P (620 mg, 0.574 mmol, 1 eq) was dissolved in pyridine (1.2 ml,15 mmol, 27 eq). Ac₂O (0.31 ml, 3.3 mmol, 5.7 eq) was added, followed byDMAP (7.0 mg, 0.057 mmol, 0.10 eq). After stirring at 20-23° C. for 3 h,the reaction mixture was diluted with toluene (12 ml) and concentrated.The same operation was repeated with toluene (12 ml×2) to give crudeproduct. The crude was purified by Biotage (Uppsala, Sweden) 25M(heptane-MTBE 7:3 v/v) to give Compound AF (541 mg, 0.482 mmol, 84%yield) as colorless oil. ¹H NMR (400 MHz, CDCl₃): δ 7.93 (2H, m), 7.66(1H, m), 7.58 (2H, m), 5.22 (1H, dd, J=3.2 Hz, 8.0 Hz), 4.98 (1H, s),4.90 (1H, s), 4.15 (1H, m), 4.12 (2H, m), 3.82 (2H, m), 3.73 (2H, m),3.44-3.57 (4H, m), 3.44 (1H, d, J=10.4 Hz), 3.38 (1H, d, J=10.4 Hz),3.37 (3H, s), 3.12 (1H, dd, J=4.0 Hz, 14.0 Hz), 2.96 (1H, dd, J=10.4 Hz,14.0 Hz), 2.63 (1H, m), 2.46 (1H, dd, J=8.8 Hz, 13.6 Hz), 2.37 (1H, dd,J=6.8 Hz, 13.6 Hz), 2.11 (1H, m), 2.04 (3H, s), 1.92 (2H, m), 1.45-1.85(12H, m), 1.16 (9H, s), 1.01 (3H, d, J=6.8 Hz), 0.85 (18H, s), 0.06 (6H,s), 0.02 (6H, s); ¹³C NMR (100 MHz, CDCl₃): δ 178.74, 170.37, 152.99,139.98, 134.14, 129.69 (2C), 128.08 (2C), 110.14, 85.58, 81.24, 81.07,78.42, 76.39, 75.54, 73.52, 71.47, 68.96, 68.01, 64.27, 57.97, 57.56,43.88, 43.82, 39.94, 38.94, 37.83, 33.54, 33.40, 32.72, 28.13, 27.43(3C), 26.21 (3C), 26.17 (3C), 25.51, 25.03, 22.21, 21.56, 20.29, 18.59,18.38, −3.87, −4.48, −5.09 (2C).

Compound AE

Zinc powder (1.54 g, 23.6 mmol, 50 eq) was suspended in water (1.1 ml)and cooled to 0° C. AcOH (0.40 ml, 7.1 mmol, 15 eq) was added at 0° C. Asolution of Compound AF (530 mg, 0.473 mmol, 1 eq) in THF (2.7 ml) wasadded at 0° C., and the mixture was allowed to warm to 20° C. After 3 h,the reaction mixture was filtered for removal of zinc powder. Thereactor was rinsed with a mixture of THF (1.1 ml) and water (1.1 ml).The filtrate was diluted with MTBE (10.6 ml), sequentially washedwith: 1) 20 wt % Rochelle salt (aqueous solution, 2.7 g, 4.0 eq), 2)saturated NaHCO₃ (6.0 g), and 3) 20 wt % NaCl (aqueous solution, 2.6 g),and concentrated to give crude product as colorless oil. The crude waspurified by Biotage (Uppsala, Sweden) 25M (heptane-MTBE 1:1 v/v) to giveCompound AE (393 mg, 0.394 mmol, 83% yield) as colorless oil. ¹H NMR(400 MHz, CDCl₃): δ 7.93 (2H, m), 7.66 (1H, m), 7.58 (2H, m), 5.23 (1H,t, J=6.4 Hz), 5.05 (1H, s), 4.95 (1H, d, J=1.6 Hz), 4.88 (1H, s), 4.83(1H, d, J=1.6 Hz), 4.33 (1H, br), 4.02 (3H, m), 3.83 (2H, m), 3.76 (1H,m), 3.60 (1H, m), 3.54 (1H, dd, J=5.6 Hz, 10.4 Hz), 3.47 (2H, m), 3.37(3H, s), 3.15 (1H, dd, J=4.0 Hz, 14.0 Hz), 2.95 (1H, dd, J=10.0 Hz, 14.0Hz), 2.83 (1H, d, J=5.2 Hz), 2.65 (2H, m), 2.40 (1H, m), 2.23 (1H, m),2.03 (3H, s), 1.96-2.03 (2H, m), 1.81 (1H, m), 1.67-1.80 (3H, m),1.40-1.67 (7H, m), 1.17 (9H, s), 1.01 (3H, d, J=6.8 Hz), 0.86 (18H, s),0.06 (6H, s), 0.03 (6H, s); ¹³C NMR (100 MHz, CDCl₃): δ 178.80, 170.77,153.18, 151.49, 139.77, 134.16, 129.67 (2C), 128.16 (2C), 109.77,105.27, 85.84, 80.92, 80.15, 78.57, 76.97, 74.59, 71.51, 68.80, 68.05,64.43, 58.01, 57.56, 45.21, 43.49, 39.78, 38.94, 34.58, 33.55, 32.28,31.77, 31.74, 27.42 (3C), 26.21 (3C), 26.17 (3C), 25.49, 22.78, 21.51,18.60, 18.39, −3.87, −4.51, −5.11 (2C).

ER-804028

Compound AE (280 mg, 0.281 mmol, 1 eq) was dissolved in CH₂Cl₂ andcooled to 0° C. Pyridine (0.045 ml, 0.56 mmol, 2.0 eq) was addedfollowed by Ms₂O (58.8 mg, 0.338 mmol, 1.20 eq). The reaction wasallowed to warm to room temperature, and stirring was continued for anadditional 1 h. The reaction mixture was cooled to 0° C., diluted withMTBE (5.6 ml), washed with saturated NaHCO₃ (0.84 g), and concentratedto give crude product as colorless film. The crude was azeotropicallydried with heptane (3 ml×2) and re-dissolved in THF (7.0 ml). Themixture was cooled to 0° C. and treated with 25 wt % NaOMe (0.13 ml).After 10 min, the reaction was allowed to warm to room temperature, andstirring was continued for an additional 30 min. The mixture was treatedwith additional 25 wt % NaOMe (0.045 ml), and stirring was continued foran additional 20 min. The reaction mixture was diluted with heptane (7.0ml) and washed with water (1.4 ml). The organic layer was separated,sequentially washed with: 1) 20 wt % NH₄Cl (0.84 g) and 2) 20 wt % NaCl(3 g), and concentrated to give crude product as brownish oil. The crudewas purified by Biotage (Uppsala, Sweden) 12M (heptane-MTBE 2:3 v/v) togive ER-804028 (209 mg, 0.245 mmol, 87%) as pale yellow oil. ¹H NMR (400MHz, CDCl₃): δ 7.89 (2H, m), 7.64 (1H, m), 7.56 (2H, m), 4.85 (1H, d,J=1.6 Hz), 4.80 (1H, s), 4.72 (1H, s), 4.61 (1H, d, J=1.6 Hz), 4.23 (1H,br), 3.91 (1H, m), 3.79 (1H, m), 3.76 (2H, m), 3.63 (1H, m), 3.50-3.60(4H, m), 3.43 (1H, dd, J=5.6 Hz, 10.0 Hz), 3.38 (3H, s), 3.32 (1H, m),2.98 (2H, m), 2.61 (1H, br), 2.56 (1H, m), 2.50 (1H, m), 2.08-2.22 (3H,m), 1.96 (1H, m), 1.84 (1H, m), 1.78 (1H, m), 1.70 (1H, m), 1.42-1.63(6H, m), 1.28-1.42 (2H, m), 1.01 (3H, d, J=6.8 Hz), 0.84 (18H, s), 0.05(3H, s), 0.04 (3H, s), 0.00 (3H, s), −0.01 (3H, s); and ¹³C NMR (100MHz, CDCl₃): δ 150.34, 150.75, 139.91, 134.18, 129.73 (2C), 128.14 (2C),105.10, 85.97, 80.92, 79.72, 78.50, 77.45, 77.09, 75.53, 71.59, 68.04,62.88, 58.27, 57.73, 43.51, 42.82, 39.16, 37.68, 35.69, 33.31, 32.41,31.89, 31.48, 29.79, 26.21 (3C), 26.17 (3C), 18.58, 18.38, 18.13, −3.85,−4.71, −5.12 (2C).

Alternate Route to Compound W Compound F

Compound D (0.657 g, 2.11 mmol, 1 eq) was dissolved in DMF (1.3 ml) andcooled to 0° C. Imidazole (0.287 g, 4.22 mmol, 2.00 eq) was added,followed by TBDPSCl (0.576 ml, 2.22 mmol, 1.05 eq). The mixture wasstirred at 0-5° C. for 1 h and allowed to warm to room temperature.After stirring overnight (16 h), the reaction mixture was diluted withwater (5.2 ml) and extracted with MTBE (5.2 ml). The organic layer wasseparated and set aside. The aqueous layer was extracted with MTBE (5.2ml). All organic layers were combined, washed with water (2.6 ml), andconcentrated to give crude Compound X:

as pale yellow oil. Compound X (2.11 mmol assumed, 1 eq) was dissolvedin toluene (4.6 ml) and cooled to −5° C. 2.0 M LiBH₄ (solution in THF,2.43 ml, 4.85 mmol, 2.30 eq) was added while maintaining T-internal <0°C. A mixture of MeOH (0.196 ml, 4.85 mmol, 2.30 eq) and toluene (0.80ml) was added at <0° C., and then reaction was allowed to warm to 20-22°C. After 22 h, the reaction mixture was carefully/slowly poured into apre-chilled (0° C.) mixture of 20 wt % citric acid (aqueous solution,6.0 g, 6.2 mmol, 3.0 eq) and MTBE (20 ml) while maintaining T-internal<10° C. The organic layer was separated, sequentially washed with: 1)saturated NaHCO₃ (3.0 g) and 2) water (3.0 g), and concentrated to givecrude Compound Y:

Compound Y (2.11 mmol assumed, 1 eq) was dissolved in CH₂Cl₂ (2.5 ml) atroom temperature. TEA (0.441 ml, 3.16 mmol, 1.50 eq) was added followedby DMAP (26 mg, 0.21 mmol, 0.10 eq). The mixture was cooled to 0° C. andtreated with pivaloyl chloride (0.272 ml, 2.22 mmol, 1.05 eq). Thereaction was allowed to warm to room temperature and stirring wascontinued overnight (16 h). The reaction mixture was diluted with MTBE(10 ml), sequentially washed with: 1) 20 wt % citric acid (aqueoussolution, 3.0 g, 1.5 eq) and 2) saturated NaHCO₃ (aqueous solution, 3.0g), and concentrated to give crude product as orange-colored oil. Thecrude was purified by Biotage (Uppsala, Sweden) 25M (heptane-MTBE 7:3v/v) to give Compound F (0.920 g, 1.52 mmol, 72% overall yield) ascolorless oil.

Compound M

Zinc dust (982 mg, 15.0 mmol, 10.0 eq) was suspended in THF (1.8 ml),and MsOH (0.0097 ml, 0.15 mmol, 0.10 eq) was added. The resultantmixture was heated at reflux for 30 min and then cooled to 20° C. Asolution of Compound F (910 mg, 1.50 mmol, 1 eq) and t-butylbromoacetate (0.222 ml, 15.0 mmol, 1.00 eq) in THF (4.6 ml) was added,and the mixture was heated at reflux. After 2 h, t-butyl bromoacetate(0.222 ml, 1.50 mmol, 1.00 eq) was added, and heating was continued for4 h. t-Butyl bromoacetate (0.111 ml, 1.50 mmol, 0.50 eq) was added, andheating was continued for an additional 6 h. After cooling down, thereaction mixture was diluted with MTBE (14 ml) and cooled to 0° C. 20 wt% citric acid (aqueous solution, 7.2 g, 7.5 mmol, 5.0 eq) was added at<10° C., and vigorous stirring was continued for 10 min. The wholebiphasic mixture was filtered for removal of Zn. The reactor and Zn wererinsed with MTBE (9 ml). The organic layer was separated, sequentiallywashed with: 1) saturated NaHCO₃ (aqueous solution, 3.8 g) and 2) 20 wt% NaCl (2.7 g), and concentrated to give crude Compound I as pale yellowoil. Compound I (1.50 mmol assumed, 1 eq) was suspended in THF (2.5ml)-water (1.5 ml) and treated with AcOH (4.5 ml, 7.9 mmol) at roomtemperature for 2 h. The reaction mixture was diluted with toluene (20ml) and concentrated. The same operation was repeated with toluene (20ml×2) to give crude Compound Z:

The crude was purified by Biotage (Uppsala, Sweden) 25M (heptane-MTBE4:1 v/v) to give Compound Z (1.062 g, 1.47 mmol, 97% yield) as colorlessoil.

Compound Z (1.00 g, 1.38 mmol, 1 eq) was dissolved in CH₂Cl₂ (9.0 ml)and treated with TFA (1.00 ml, 13.0 mmol) at room temperature. After 4h, the reaction mixture was diluted with toluene (15 ml) andconcentrated. The same operation was repeated with toluene (15 ml×2) togive crude Compound K. Compound K was dissolved in toluene (10 ml),heated at 100° C. for 30 min, and concentrated to give crude Compound M.The crude was purified by Biotage (Uppsala, Sweden) 25M (heptane-MTBE7:3 v/v) to give Compound M (775 mg, 1.24 mmol, 90% yield) as colorlessoil.

Compound W

Compound M (745 mg, 1.20 mmol, 1 eq) was dissolved in THF (4.5 ml) andPhNTf₂ (641 mg, 1.79 mmol, 1.50 eq) was added at 20° C. Upon completedissolution of PhNTf₂, the mixture was cooled to −23° C. 0.5 M KHMDS(solution in toluene, 2.63 ml, 1.32 mmol, 1.10 eq) was added whilemaintaining T-internal <−18° C., and the mixture was stirred at −18 to−20° C. for 1 h. Under vigorous stirring, 20 wt % NH₄Cl (aqueoussolution, 0.32 g) was added while maintaining T-internal <−10° C., andthen the mixture was allowed to warm to 0° C. The mixture was dilutedwith MTBE (7.5 ml) and water (0.74 ml), and vigorous stirring wascontinued for 5 min. The organic layer was separated, washed with water(1.5 ml), and concentrated to give crude Compound AA:

as yellow solid-oil. Compound AA was dissolved in CH₃CN (9.0 ml) andtreated with 49 wt % HF (aqueous solution, 3.0 g) at room temperaturefor 20 h. The reaction mixture was carefully/slowly poured into apre-chilled (0° C.) mixture of MTBE (40 ml), water (7.5 ml), and NaHCO₃(8.5 g) while maintaining T-internal <10° C. The organic layer wasseparated and set aside. The aqueous layer was extracted with MTBE (7.5ml). All organic layers were combined, washed with 20 wt % NaCl (aqueoussolution, 3.7 g), and concentrated to give crude Compound W as yellowsolid-oil. The crude was purified by Biotage (Uppsala, Sweden) 25M(heptane-MTBE 1:1 & 2:3 v/v) to give Compound W (522 mg, 1.01 mmol, 84%yield) as pale yellow oil.

Alternate Route to Compound L Compound H

Zinc (1.06 g, 16.2 mmol, 10 eq) was suspended in THF (2.3 ml). MsOH(0.010 ml, 0.02 mmol, 0.1 eq) was added at room temperature, and theresultant slurry was heated at reflux for 30 min. After cooling down, amixture of Compound X (780 mg, 1.62 mmol, 1 eq) and benzhydrylbromoacetate (0.74 g, 2.4 mmol, 1.5 eq; Kume et al., Tetrahedron, 1997,53, 1635) in THF (3.9 ml) was added, and the reaction was heated toreflux. After heating for 3 h, benzhydryl bromoacetate (0.74 g, 2.4mmol, 1.5 eq) was added, and heating was continued for an additional 7h. After cooling down, the mixture was diluted with MTBE (16 ml) andfiltered through a pad of Celite (1.6 g). The filtrate was sequentiallywashed with: 1) 20 wt % citric acid (aqueous solution, 3.9 g), 2) 10 wt% NaHCO₃ (aqueous solution, 3.9 g), and 3) 20 wt % NaCl (aqueoussolution, 2.3 g), and concentrated to give crude product as yellow oil.The crude was purified by Biotage (Uppsala, Sweden) 40M (heptane-MTBE1:1 v/v) to give Compound H as pale yellow oil (770 mg, 1.08 mmol, 67%yield).

Compound AB

Compound H (770 mg, 1.08 mmol, 1 eq) was dissolved in THF (0.77 ml) andcooled to 0° C. Water (0.38 ml) was added followed by AcOH (1.54 ml).The mixture was allowed to warm to room temperature, and stirring wascontinued for 8 h. The reaction mixture was diluted with toluene (15 ml)and concentrated. The residue was further azeotroped with toluene (15ml×2) and purified by Biotage (Uppsala, Sweden) 25M (heptane-MTBE 2:1v/v) to give Compound AB (716 mg, 1.01 mmol, 93% yield) as pale yellowoil.

Compound L

Compound AB (716 mg, 1.01 mmol, 1 eq) was hydrogenated with 10 wt % Pd—C(wet-type, 0.11 g, 0.050 mmol, 0.05 eq), H₂ (balloon), and EtOAc (7.2ml) for 2 h. The reaction mixture was filtered, concentrated, andre-dissolved in toluene (7.2 ml). The mixture was heated at 100° C. for15 min. After cooling down, the mixture was concentrated and purified byBiotage (Uppsala, Sweden) 25M (heptane-MTBE 2:1 v/v) to give Compound L(476 mg, 0.954 mmol, 95% yield) as colorless oil.

Compound AJ

Compound AI was synthesized from ER-806730 (WO 2005/118565, Example 2)by iodo-etherification with N-iodosuccinimide in acetonitrile.

Compound AI (2.95 g, 5.44 mmol, 1 eq) was dissolved in pyridine (3.0 ml,36 mmol, 6.7 eq) and treated with phthalic anhydride (0.846 g, 5.71 mol,1.05 eq) at room temperature for 18 h. The reaction mixture was dilutedwith MTBE (200 ml), sequentially washed with: 1) 20 wt % citric acid (35g); 2) 20 wt % citric acid (35 g); 3) water (9 g); and 4) water (9 g),and concentrated to give crude product as pale yellow oil. The crude waspurified by Biotage (Uppsala, Sweden) 25M (heptane-MTBE 1:1 & MTBE 100%)to give Compound AJ as colorless oil (3.20 g, 4.63 mmol, 85% yield). ¹HNMR (400 MHz, CDCl₃): δ 7.83 (1H, m), 7.71 (1H, m), 7.53-7.59 (2H, m),5.08 (1H, d, J=3.6 Hz), 5.01 (1H, d, J=3.6 Hz), 4.51 (1H, m), 4.27 (1H,m), 4.20 (1H, m), 3.87 (1H, dd, J=6.0 Hz, 9.2 Hz), 3.54 (1H, m), 3.50(1H, d, J=10.8 Hz), 3.48 (1H, d, J=10.8 Hz), 2.84 (1H, m), 2.33 (1H, dd,J=8.8 Hz, 13.6 Hz), 1.83-1.94 (2H, m), 1.46-1.80 (8H, m), 1.22 (1H, m),1.13 (3H, d, J=6.8 Hz).

Compound AK

Compound P (0.050 g, 0.046 mmol, 1 eq) was dissolved in THF (0.30 mL)and treated with NaOMe (25 wt % solution in MeOH, 0.10 ml, 0.44 mmol,9.4 eq) at room temperature for 1 h. The reaction mixture was dilutedwith MTBE (3.0 ml), sequentially washed with: 1) water (0.30 g); 2)water (0.30 g); and 3) 20 wt % NaCl (0.30 g), and concentrated to givecrude product as colorless oil. The crude product was purified bypreparative TLC (MTBE 100%) to give Compound AK as colorless film (33mg, 0.033 mmol, 72% yield).

Compounds AL and AM

Compound AK (0.175 g, 0.176 mmol, 1 eq) was dissolved in pyridine (0.56ml, 6.9 mmol, 39 eq). 4-methoxybenzoly chloride (0.066 g, 0.39 mmol, 2.2eq) was added at room temperature, and the mixture was stirred for 15 h.The reaction mixture was diluted with MTBE (7 ml) and washed with 20 wt% citric acid (7 g). The organic layer was separated and set aside. Theaqueous layer was extracted with MTBE (7 ml). All organic layers werecombined, sequentially washed with 20 wt % citric acid (3 g) and water(3 g), and concentrated to give crude product as pale yellow oil. Thecrude product was purified by Biotage (Uppsala, Sweden) 12M KP-Sil(heptane-MTBE 7:3 & 1:1) to give Compound AL (0.02 g, 0.02 mmol, 9%yield, colorless film) and Compound AM (0.14 g, 0.12 mmol, 70% yield,colorless oil). Compound AM: ¹H NMR (400 MHz, CDCl₃) δ 7.95 (2H, d,J=8.8 Hz), 7.89 (2H, d, J=7.2 Hz), 7.65 (1H, m), 7.57 (2H, m), 6.87 (2H,d, J=8.8 Hz), 5.18 (1H, s), 4.85 (1H, s), 4.26 (2H, m), 4.20 (1H, m),4.12 (1H, m), 3.92 (1H, m), 3.83 (3H, s), 3.70-3.80 (3H, m), 3.53 (1H,m), 3.40-3.50 (4H, m), 3.36 (3H, s), 3.08 (2H, m), 2.57 (1H, m), 2.38(1H, dd, J=9.2 Hz, 14 Hz), 2.29 (1H, m), 1.98 (1H, m), 1.71-1.92 (7H,m), 1.52-1.68 (7H, m), 1.48 (1H, m), 1.18 (1H, m), 1.04 (3H, d, J=7.2Hz), 0.86 (9H, s), 0.84 (9H, s), 0.05 (6H, s), 0.02 (3H, s), 0.01 (3H,s).

Synthesis of Compound AD and Synthesis of Compound P from Compound AD

Compound AD

Compound AD was prepared in the process of producing a mixture ofCompound P with its C27 diastereomer. Compound P (50.2 mg, 0.0465 mmol,1 eq) was dissolved in CH₂Cl₂ (0.50 ml). Dess-Martin periodinane (23.6mg, 0.0556 mol, 1.2 eq) was added at room temperature. After 10 min,NaHCO₃ (40 mg, 0.5 mmol) was added followed by isopropyl alcohol (0.014ml, 0.19 mol, 4 eq), and stirring was continued for an additional 1 h.The mixture was diluted with MTBE (2 ml), washed with water (0.5 ml),and concentrated to give crude product as a colorless oil. The crude waspurified by Biotage (Uppsala, Sweden) 12M (heptane-MTBE 7:3 & 1:1) togive Compound AD (42 mg, 0.039 mmol, 84% yield) as a colorless oil. ¹HNMR (400 MHz, CDCl₃): δ 7.92 (2H, m), 7.63 (1H, m), 7.56 (2H, m), 5.96(1H, s), 5.74 (1H, s), 4.15 (1H, m), 4.04 (2H, m), 3.94 (1H, d, J=3.2Hz), 3.89 (2H, m), 3.75 (2H, m), 3.54 (2H, m), 3.39 (3H, s), 3.44 (1H,m), 3.43 (1H, d, J=10.4 Hz), 3.34 (1H, d, J=10.4 Hz), 3.19 (1H, m), 3.02(1H, dd, J=10.8 Hz, 14 Hz), 2.98 (1H, dd, J=8.0 Hz, 17.2 Hz), 2.81 (1H,m), 2.42 (1H, m), 2.31 (1H, dd, J=8.8 Hz, 14 Hz), 1.98 (1H, m),1.45-1.85 (12H, m), 1.17 (9H, s), 1.02 (3H, d, J=7.2 Hz), 0.87 (9H, s),0.86 (9H, s), 0.07 (3H, s), 0.06 (3H, s), 0.03 (3H, s), 0.02 (3H, s).

Compound P

Compound P can also be obtained from reduction of Compound AD, made byany means. Compound AD (33 mg, 0.031 mmol) was dissolved in toluene(0.50 ml) and cooled to 0° C. 2.0 M LiBH₄ (solution in THF, 8 μl) wasadded at 0° C., and stirring was continued at 0° C. for 10 min. 2.0 MLiBH₄ (solution in THF, 8 μl) was added, and stirring was continued foran additional 10 min. The reaction mixture was diluted with MTBE (1.0ml), sequentially washed with 20 wt % citric acid (aqueous solution,0.20 g) and saturated NaHCO₃ (aqueous solution, 0.20 g), andconcentrated to give crude product. The crude was purified bypreparative TLC (heptane-MTBE 2:3) to give Compound P (24 mg, 72% yield,C27-dr 5:1).

Other Embodiments

All publications, patents, and patent application publications mentionedherein are hereby incorporated by reference. Various modifications andvariations of the described compounds of the invention will be apparentto those skilled in the art without departing from the scope and spiritof the invention. Although the invention has been described inconnection with certain embodiments, it should be understood that theinvention as claimed should not be unduly limited to such embodiments.Indeed, various modifications of the described modes for carrying outthe invention that are obvious to those skilled in the relevant art areintended to be within the scope of the invention.

What is claimed is:
 1. (canceled)
 2. A method for producing eribulin ora pharmaceutically acceptable salt thereof, said method comprising: (i)reacting the compound having the formula (I):

wherein X is halogen or oxo; Z is a leaving group; Q is —C(O)H,—CH═CHC(O)OY₁, —C(R)H(CH₂)_(n)OY₁, or —C(R)HCH₂C(O)OY₁; R is H or —OY₂;Y₁ and Y₂ are each independently H or a hydroxyl protecting group; and nis 1 or 2, with a compound having the formula (IV):

wherein Y₃ and Y₄, are each independently H or a hydroxyl protectinggroup, under NHK coupling conditions to produce the compound having theformula (II):

wherein X is halogen or oxo; Q is —C(O)H, —CH═CHC(O)OY₁,—C(R)H(CH₂)_(n)OY₁, or —C(R)HCH₂C(O)OY₁; R is H or —OY₂; n is 1 or 2;Y₁, Y₂, Y₃, and Y₄ are each independently H or a hydroxyl protectinggroup; T is oxo or —OY₅; and Y₅ is H or a hydroxyl protecting group, orY₅, together with the oxygen atom to which it is bound, is a leavinggroup; (ii) reacting the product of step (i) under Vasella fragmentationconditions to produce a compound having the formula (III):

wherein Q is —C(O)H, —CH═CHC(O)OY₁, —C(R)H(CH₂)_(n)OY₁, or—C(R)HCH₂C(O)OY₁; R is H or —OY₂; n is 1 or 2; Y₁, Y₂, Y₃, and Y₄ areeach independently H or a hydroxyl protecting group; U is —OY₆; Y₅ is Hor a hydroxyl protecting group or Y₅, together with the oxygen atom towhich it is bound, is a leaving group; and Y₆ is H or a hydroxylprotecting group or Y₆, together with the oxygen atom to which it isbound, is a leaving group, provided that when Q is —(CH₂)₃OY₁, —OY₆ is aleaving group, and Y₁, Y₃, and Y₄ are protecting groups, Y₅ is not H;(iii) reacting the product of step (ii) under conditions forintramolecular Williamson etherification to produce ER-804028:

and (iv) converting ER-804028 into eribulin or a pharmaceuticallyacceptable salt thereof.
 3. The method of claim 2, wherein the compoundof formula (I) has formula (Ia):


4. The method of claim 2, wherein Q is —(CH₂)₃OY₁.
 5. The method ofclaim 2, wherein, in the compound of formula (I), Y₁, together with theoxygen to which it is bound, is an ester, carbonate, carbamate,sulfonate, or ether hydroxyl protecting group.
 6. The method of claim 2,wherein, in the compound of formula (I), Y₁ is pivaloyl, acetyl,benzoyl, p-bromobenzoyl, p-methoxybenzoyl, 1-naphthoyl, 2-naphthoyl,o-phthaloyl, benzyl, p-methoxybenzyl, triphenylmethyl, tri(C1-C6alkyl)silyl, tri(C6-C10 aryl or C1-C6 heteroaryl)silyl, di(C6-C10 arylor C1-C6 heteroaryl)(C1-C6 alkyl)silyl, or (C6-C10 aryl or C1-C6heteroaryl)di(C1-C6 alkyl)silyl.
 7. The method of claim 2, wherein X ishalogen.
 8. The method of claim 2, wherein Z is halogen or(C1-C6)alkylsulfonate.
 9. The method of claim 2, wherein Z is triflate,iodide, or bromide.
 10. The method of claim 2, wherein the compound offormula (I) has formula (Ib):

wherein Y₁ is H, pivaloyl, benzoyl, p-bromobenzoyl, 1-naphthoyl,2-naphthoyl, p-methoxybenzoyl, or o-phthaloyl or a salt thereof.
 11. Themethod of claim 2, wherein the compound of formula (II) has formula(IIa):


12. The method of claim 2, wherein the compound of formula (II) hasformula (IIb):


13. The method of claim 2, wherein, in the compound of formula (II), Qis —(CH₂)₃OY₁; Y₁, together with the oxygen atom to which it is bound,is an ester, carbonate, carbamate, sulfonate, or ether hydroxylprotecting group; each of Y₃ and Y₄ is, independently and together withthe oxygen atom to which it is bound, an ester, carbonate, carbamate,sulfonate, or ether hydroxyl protecting group, or Y₃ and Y₄ togetherwith the oxygen atoms to which they are bound are a cyclic carbonate,cyclic boronate, or cyclic silylene hydroxyl protecting group, or Y₃ andY₄ together are acetal, ketal, or 1,1,3,3-tetraisopropylsiloxanediyl; Tis —OY₅; and Y₅, together with the oxygen atom to which it is bound, isan ester, carbonate, carbamate, sulfonate, or ether hydroxyl protectinggroup.
 14. The method of claim 2, wherein, in the compound of formula(II), Y₁ is pivaloyl, acetyl, benzoyl, p-bromobenzoyl, p-methoxybenzoyl,1-naphthoyl, 2-naphthoyl, o-phthaloyl, benzyl, p-methoxybenzyl,triphenylmethyl, tri(C1-C6 alkyl)silyl, tri(C6-C10 aryl or C1-C6heteroaryl)silyl, di(C6-C10 aryl or C1-C6 heteroaryl)(C1-C6 alkyl)silyl,or (C6-C10 aryl or C1-C6 heteroaryl)di(C1-C6 alkyl)silyl.
 15. The methodof claim 2, wherein, in the compound of formula (II), Y₃ and Y₄ are eachindependently tri(C1-C6 alkyl)silyl, tri(C6-C10 aryl or C1-C6heteroaryl)silyl, di(C6-C10 aryl or C1-C6 heteroaryl)(C1-C6 alkyl)silyl,or (C6-C10 aryl or C1-C6 heteroaryl)di(C1-C6 alkyl)silyl, or Y₃ and Y₄are together di(C1-C6alkyl)silylene.
 16. The method of claim 2, wherein,in the compound of formula (II), Y₅ is acetyl, benzoyl, p-bromobenzoyl,p-methoxybenzoyl, 1-naphthoyl, 2-naphthoyl, or o-phthaloyl.
 17. Themethod of claim 2, wherein the compound of formula (II) has formula(IIc):

wherein Y₁ and Y₅ are as follows: Y₁ Y₅ H H benzoyl benzoylp-bromobenzoyl p-bromobenzoyl pivaloyl H pivaloyl acetyl pivaloylbenzoyl 2-naphthoyl H 2-naphthoyl 2-naphthoyl 1-naphthoyl H 1-naphthoyl1-naphthoyl p-methoxybenzoyl H p-methoxybenzoyl p-methoxybenzoylo-phthaloyl or salt thereof H.


18. The method of claim 2, wherein the compound of formula (II) is:


19. The method of claim 2, wherein the compound of formula (III) hasformula (IIIa):


20. The method of claim 2, wherein, in the compound of formula (III), Qis —(CH₂)₃OY₁; Y₁, together with the oxygen atom to which it is bound,is an ester, carbonate, carbamate, sulfonate, or ether hydroxylprotecting group; Y₃ and Y₄ are each, independently and together withthe oxygen atom to which it is bound, an ester, carbonate, carbamate,sulfonate, or ether hydroxyl protecting group, or Y₃ and Y₄ togetherwith the oxygen atoms to which they are bound are a cyclic carbonate,cyclic boronate, or cyclic silylene hydroxyl protecting group, or Y₃ andY₄ together are acetal, ketal, or 1,1,3,3-tetraisopropylsiloxanediyl;and Y₅, together with the oxygen atom to which it is bound, is an ester,carbonate, carbamate, sulfonate, or ether hydroxyl protecting group. 21.The method of claim 2, wherein, in the compound of formula (III), Y₁ ispivaloyl, acetyl, benzoyl, p-bromobenzoyl, p-methoxybenzoyl,1-naphthoyl, 2-naphthoyl, o-phthaloyl, benzyl, p-methoxybenzyl,triphenylmethyl, tri(C1-C6 alkyl)silyl, tri(C6-C10 aryl or C1-C6heteroaryl)silyl, di(C6-C10 aryl or C1-C6 heteroaryl)(C1-C6 alkyl)silyl,or (C6-C10 aryl or C1-C6 heteroaryl)di(C1-C6 alkyl)silyl.
 22. The methodof claim 2, wherein, in the compound of formula (III), Y₃ and Y₄ areeach independently tri(C1-C6 alkyl)silyl, tri(C6-C10 aryl or C1-C6heteroaryl)silyl, di(C6-C10 aryl or C1-C6 heteroaryl)(C1-C6 alkyl)silyl,or (C6-C10 aryl or C1-C6 heteroaryl)di(C1-C6 alkyl)silyl, or Y₃ and Y₄are together di(C1-C6)alkylsilylene.
 23. The method of claim 2, wherein,in the compound of formula (III), Y₅ is acetyl, benzoyl, p-bromobenzoyl,p-methoxybenzoyl, 1-naphthoyl, 2-naphthoyl, or o-phthaloyl.
 24. Themethod of claim 2, wherein, in the compound of formula (III), Y₅ is H ora hydroxyl protecting group.
 25. The method of claim 2, wherein, in thecompound of formula (III), Y₆ is H.
 26. The method of claim 2, wherein,in the compound of formula (III), —OY₆ is a leaving group.
 27. Themethod of claim 26, wherein, in the compound of formula (III), —OY₆ is(C1-C6)alkylsulfonate, (C6-C10 aryl or C1-C6 heteroaryl)sulfonate,(C6-C15)aryl(C1-C6)alkylsulfonate, or(C1-C6)heteroaryl(C1-C6)alkylsulfonate.
 28. The method of claim 27,wherein, in the compound of formula (III), —OY₆ is mesylate,toluenesulfonate, isopropylsulfonate, phenylsulfonate, orbenzylsulfonate.
 29. The method of claim 2, wherein the compound offormula (III) is